**3.1.1.1 Microorganisms**

*Kluyveromyces marxianus* 499 obtained from Institute of Agricultural and Food Biotechnology Warsaw, Poland, in lyophilized form was used in all experiments. The yeast strain was cultivated on plates prepared with Wort Agar growth media from Merck Company Darmstadt (Germany) with the addition of 3% lactose using an incubator shaker under sterile conditions at pH 4.5 and a temperature 25ºC for 48 h. The yeast was aseptically transferred from the plates into 300 ml cultivation flasks containing 100 ml of Wort Agar medium from Merck Company Darmstadt (Germany) supplemented with 3% lactose, and cultivated at 25ºC for 24 h on a rotatory shaker. The yeast culture was immobilized and suspended in 2% w/v sodium alginate and then added drop-wise to 1.5% w/v CaCl2 solution. The CaCl2 was decanted. The beads were used for inoculation of experimental reactors.
